Installing VirtualBox Guest Additions in Ubuntu
VirtualBox Guest Additions is also a part of VirtualBox which adds some extra features to your virtual machine. i.e, optimizes graphics, USB support, file and clipboard sharing, etc.
When you are done with Ubuntu installation, you must have noticed that screen size is pretty small, and you are not able to change it. That is when Guest Additions are used.
If you want better performance on your virtual machine, you must install VirtualBox Guest Additions. We have shown you how to install VirtualBox and Ubuntu inside it, but the newly installed virtual machines has some restrictions like inability to run in full screen mode, sharing folders and clipboard, etc. In fact there is also a room for improved performance which can be achieved by installing VirtualBox Guest Additions.
Before installing Guest Additions, make sure your user account has root privilege. If you followed our guide How to install Ubuntu on Oracle VirtualBox then it will probably have them already.
If you are not sure about it, just run the following command in terminal. Please note that you must run this command from a root user account.
sudo adduser USERNAME sudo
where USERNAME should be replaced by the current user’s name.
To install Guest Additions, click Devices > Insert Guest Additions CD images…
Click ‘Run‘ button (next to ‘Cancel’ button) to start the installation. Note that the version of VBOXADDITIONS should be matched with the one of VirtualBox you have installed.
Installing Guest Additions requires root privilege. Enter user’s password (I am assuming the current user has sudo privilege).
When the installation is finished, press Return or Enter key to close the terminal window.
Now prepare to restart the system to enable the change. Click ‘Shutdown‘ on the menu and then the ‘Restart‘ button.
After rebooting Ubuntu, you will see the desktop resolution is much better.
Shared Folders enables sharing of a folder between the host and guest operating systems. Everything that you add into the shared folder it is available to both operating systems.
To enable Shared Folder you should have VirtualBox Guest Additions installed.
When Ubuntu is running, click on Devices > Shared folders settings…
Select Machine Folders and hit the add button (plus sign).
Browse to the folder you wish to access from the guest machine. Check Auto-mount and Make Permanent options and click OK button.
Click OK button once more.
Now type ‘terminal‘ in Dash to open a Terminal.
Enter this command to add a user to ‘vboxsf‘ group. This is a very important for sharing the folder via a virtual network.
sudo adduser USERNAME vboxsf
Again, replace USERNAME with your username.
Then restart the Ubuntu guest machine and go to /media/ directory. By accessing to Computer > File System > Media folder and inside it you will see a folder beginning with sf_ (the folder name is sf_Downloads in our example). Now you can transfer files between the Ubuntu guest machine and the Windows host machine.
Please let us know in the comments if you need any help.